"Richard Casady" wrote in message
...
On Thu, 9 Oct 2008 10:52:19 -0700 (PDT), wrote:

On Oct 7, 5:26 pm, "Calif Bill" wrote:
"Wayne.B" wrote in message

news




On Tue, 07 Oct 2008 15:07:53 -0500, Vic Smith
wrote:

This is what I was thinking, but since my thermodynamics training is
insufficient, I'd like to enlist your help.
Besides your technical expertise (sorry I can't say the same for your
political judgement) you're down there where the water is warm.
What we need is a heat extraction process that will at least add
locomotion power to a boat.

Actually you need a temperature "difference" to extract mechanical
power. Most of the sea water power schemes that I've seen rely on
using the temp difference between warm water on top and cool water
from the depths. That might work for a stationary power plant but
would create way too much drag for a useful boat.

Thermocouples will work in heat alone. Proposals to help fuel economy by
placing thermocouples along the exhaust pipe to turn waste heat into
electrical energy.- Hide quoted text -

- Show quoted text -

Thermocouples cool themselves by generating electricity. You don't
have enough heat in the sea water for thermocouples.

Thermocouples have to have both a hot junction and a cold one to work.

Casady

Huh? Then how come the thermocouple in the heater pilot light keeps
working?

On Thu, 9 Oct 2008 17:36:54 -0700, "Calif Bill"
wrote:


"Richard Casady" wrote in message
.. .
On Thu, 9 Oct 2008 10:52:19 -0700 (PDT), wrote:

On Oct 7, 5:26 pm, "Calif Bill" wrote:
"Wayne.B" wrote in message

news




On Tue, 07 Oct 2008 15:07:53 -0500, Vic Smith
wrote:

This is what I was thinking, but since my thermodynamics training is
insufficient, I'd like to enlist your help.
Besides your technical expertise (sorry I can't say the same for your
political judgement) you're down there where the water is warm.
What we need is a heat extraction process that will at least add
locomotion power to a boat.

Actually you need a temperature "difference" to extract mechanical
power. Most of the sea water power schemes that I've seen rely on
using the temp difference between warm water on top and cool water
from the depths. That might work for a stationary power plant but
would create way too much drag for a useful boat.

Thermocouples will work in heat alone. Proposals to help fuel economy by
placing thermocouples along the exhaust pipe to turn waste heat into
electrical energy.- Hide quoted text -

- Show quoted text -

Thermocouples cool themselves by generating electricity. You don't
have enough heat in the sea water for thermocouples.

Thermocouples have to have both a hot junction and a cold one to work.

Casady

Huh? Then how come the thermocouple in the heater pilot light keeps
working?

Are you saying that all the wiring is at uniform flame temperature? I
didn't think so. What I said was that there has to a temperature
difference. Look up thermocouple in any physics text.

Wiki:Thermocouples measure the temperature difference between two
points, not absolute temperature. In traditional applications, one of
the junctions—the cold junction—was maintained at a known (reference)
temperature, while the other end was attached to a probe.


Casady

"Richard Casady" wrote in message
...
On Thu, 9 Oct 2008 17:36:54 -0700, "Calif Bill"
wrote:


"Richard Casady" wrote in message
. ..
On Thu, 9 Oct 2008 10:52:19 -0700 (PDT), wrote:

On Oct 7, 5:26 pm, "Calif Bill" wrote:
"Wayne.B" wrote in message

news




On Tue, 07 Oct 2008 15:07:53 -0500, Vic Smith
wrote:

This is what I was thinking, but since my thermodynamics training is
insufficient, I'd like to enlist your help.
Besides your technical expertise (sorry I can't say the same for
your
political judgement) you're down there where the water is warm.
What we need is a heat extraction process that will at least add
locomotion power to a boat.

Actually you need a temperature "difference" to extract mechanical
power. Most of the sea water power schemes that I've seen rely on
using the temp difference between warm water on top and cool water
from the depths. That might work for a stationary power plant but
would create way too much drag for a useful boat.

Thermocouples will work in heat alone. Proposals to help fuel economy
by
placing thermocouples along the exhaust pipe to turn waste heat into
electrical energy.- Hide quoted text -

- Show quoted text -

Thermocouples cool themselves by generating electricity. You don't
have enough heat in the sea water for thermocouples.

Thermocouples have to have both a hot junction and a cold one to work.

Casady

Huh? Then how come the thermocouple in the heater pilot light keeps
working?

Are you saying that all the wiring is at uniform flame temperature? I
didn't think so. What I said was that there has to a temperature
difference. Look up thermocouple in any physics text.

Wiki:Thermocouples measure the temperature difference between two
points, not absolute temperature. In traditional applications, one of
the junctions-the cold junction-was maintained at a known (reference)
temperature, while the other end was attached to a probe.


Casady

Wiki is mistaken. The cold junction is where the temperature can be
measured. But thermocouples are disimilar metals the cause a current to be
generated between the two metals when heat is applied. Milliamps of
current, or a real small amount. You can make your own thermocouple by
connecting the special thermocouple wire together and heat the junction.
Enough current is caused to be able to pull a solenoid if required. Very
low current solenoid, but still current generated. Check out Omega Corp.
We used to buy the thermocouple wire they manufactured.

On Thu, 9 Oct 2008 19:27:43 -0700, "Calif Bill"
wrote:

Wiki is mistaken. The cold junction is where the temperature can be
measured. But thermocouples are disimilar metals the cause a current to be
generated between the two metals when heat is applied. Milliamps of
current, or a real small amount. You can make your own thermocouple by
connecting the special thermocouple wire together and heat the junction.
Enough current is caused to be able to pull a solenoid if required. Very
low current solenoid, but still current generated. Check out Omega Corp.
We used to buy the thermocouple wire they manufactured.

The solenoid is a junction, of course. You have dissimilar wires
connected together at both ends. I have one intended to cover the
range -320F to 1800F so which end is hot or cold depends. So what?

Casady

"Richard Casady" wrote in message
...
On Thu, 9 Oct 2008 19:27:43 -0700, "Calif Bill"
wrote:

Wiki is mistaken. The cold junction is where the temperature can be
measured. But thermocouples are disimilar metals the cause a current to
be
generated between the two metals when heat is applied. Milliamps of
current, or a real small amount. You can make your own thermocouple by
connecting the special thermocouple wire together and heat the junction.
Enough current is caused to be able to pull a solenoid if required. Very
low current solenoid, but still current generated. Check out Omega Corp.
We used to buy the thermocouple wire they manufactured.

The solenoid is a junction, of course. You have dissimilar wires
connected together at both ends. I have one intended to cover the
range -320F to 1800F so which end is hot or cold depends. So what?

Casady

The only reason you need a junction at the other end is so you can have
current flow. The current is caused by the physics of the selected
dissimilar metals in contact in a heated enviroment.